Fix a union file system bug
This commit is contained in:
Gregory Nutt
parent
712a14ab25
commit
8ed9c24675
22
TODO
22
TODO
@ -1,4 +1,4 @@
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NuttX TODO List (Last updated June 22, 2015)
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NuttX TODO List (Last updated June 24, 2015)
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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This file summarizes known NuttX bugs, limitations, inconsistencies with
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@ -19,7 +19,7 @@ nuttx/
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(12) Network (net/, drivers/net)
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(5) USB (drivers/usbdev, drivers/usbhost)
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(12) Libraries (libc/, libm/)
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(12) File system/Generic drivers (fs/, drivers/)
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(11) File system/Generic drivers (fs/, drivers/)
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(8) Graphics subsystem (graphics/)
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(1) Pascal add-on (pcode/)
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(2) Build system / Toolchains
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@ -1439,24 +1439,6 @@ o File system / Generic drivers (fs/, drivers/)
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ignored by readder() logic. This the file does not
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appear in the 'ls'.
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Title: UNIONFS WITH OFFSETS
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Description: The Union File System supports offset strings to allow
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directories to appear at an offset below the union mount
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point. These offsets work in many cases (open, close, read,
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write, etc.), but there are some problems:
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1. The current test case at apps/examples/unionfs uses an
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offset string for one file system, but the offset string
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is matched by a a directory in the other file system.
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This causes many problems with the offset file system to
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be obscured.
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2. If both contained file systems are offset, then stat(),
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opendir(), readdir() etc. fail.
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3. The offsets do not work for directory operations on their
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the top level directory.
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Status: Open
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Priority: High-ish
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o Graphics subsystem (graphics/)
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -112,7 +112,9 @@ struct unionfs_file_s
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static int unionfs_semtake(FAR struct unionfs_inode_s *ui, bool noint);
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#define unionfs_semgive(ui) (void)sem_post(&(ui)->ui_exclsem)
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static FAR const char *unionfs_trypath(FAR const char *relpath,
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static FAR const char *unionfs_offsetpath(FAR const char *relpath,
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FAR const char *prefix);
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static bool unionfs_ispartprefix(FAR const char *partprefix,
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FAR const char *prefix);
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static int unionfs_tryopen(FAR struct file *filep,
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FAR const char *relpath, FAR const char *prefix, int oflags,
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@ -265,11 +267,11 @@ static int unionfs_semtake(FAR struct unionfs_inode_s *ui, bool noint)
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}
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/****************************************************************************
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* Name: unionfs_trypath
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* Name: unionfs_offsetpath
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****************************************************************************/
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static FAR const char *unionfs_trypath(FAR const char *relpath,
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FAR const char *prefix)
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static FAR const char *unionfs_offsetpath(FAR const char *relpath,
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FAR const char *prefix)
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{
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FAR const char *trypath;
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int pfxlen;
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@ -305,6 +307,84 @@ static FAR const char *unionfs_trypath(FAR const char *relpath,
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return trypath;
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}
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/****************************************************************************
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* Name: unionfs_ispartprefix
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****************************************************************************/
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static bool unionfs_ispartprefix(FAR const char *partprefix,
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FAR const char *prefix)
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{
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int partlen = 0;
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int pfxlen = 0;
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/* Trim any '/' characters in the partial prefix */
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if (partprefix != NULL)
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{
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/* Skip over any leading '/' */
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for (; *partprefix == '/'; partprefix++);
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/* Skip over any tailing '/' */
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partlen = strlen(partprefix);
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for (; partlen > 1 && partprefix[partlen - 1] == '/'; partlen--);
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}
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/* Check for NUL or empty partial prefix */
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if (partprefix == NULL || *partprefix == '\0')
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{
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/* A NUL partial prefix is always contained in the full prefix, even
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* if there is no prefix.
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*/
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return true;
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}
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/* Trim any '/' characters in the partial prefix */
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if (prefix != NULL)
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{
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/* Skip over any leading '/' */
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for (; *prefix == '/'; prefix++);
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/* Skip over any tailing '/' */
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pfxlen = strlen(prefix);
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for (; pfxlen > 1 && prefix[pfxlen - 1] == '/'; pfxlen--);
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}
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/* Check for NUL or empty full prefix */
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if (prefix == NULL || *prefix == '\0')
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{
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/* A non-NUL partial path canno be a contained in a NUL prefix */
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return false;
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}
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/* Both the partial path and the prefix are non-NULL. Check if the partial
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* path is contained in the prefix.
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*/
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if (partlen > pfxlen)
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{
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return false;
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}
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if (strncmp(partprefix, prefix, partlen) == 0)
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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/****************************************************************************
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* Name: unionfs_tryopen
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****************************************************************************/
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@ -317,7 +397,7 @@ static int unionfs_tryopen(FAR struct file *filep, FAR const char *relpath,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -351,7 +431,7 @@ static int unionfs_tryopendir(FAR struct inode *inode,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -384,7 +464,7 @@ static int unionfs_trymkdir(FAR struct inode *inode, FAR const char *relpath,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -418,7 +498,7 @@ static int unionfs_tryrename(FAR struct inode *mountpt,
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/* Is source path valid on this file system? */
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tryoldpath = unionfs_trypath(oldrelpath, prefix);
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tryoldpath = unionfs_offsetpath(oldrelpath, prefix);
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if (tryoldpath == NULL)
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{
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/* No.. return -ENOENT. This should not fail because the existence
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@ -436,7 +516,7 @@ static int unionfs_tryrename(FAR struct inode *mountpt,
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* delete.
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*/
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trynewpath = unionfs_trypath(newrelpath, prefix);
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trynewpath = unionfs_offsetpath(newrelpath, prefix);
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if (trynewpath == NULL)
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{
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/* No.. return -ENOSYS. We should be able to do this, but we can't
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@ -469,7 +549,7 @@ static int unionfs_trystat(FAR struct inode *inode, FAR const char *relpath,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -511,7 +591,7 @@ static int unionfs_trystatdir(FAR struct inode *inode,
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}
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/****************************************************************************
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* Name: unionfs_trystatdir
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* Name: unionfs_trystatfile
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****************************************************************************/
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static int unionfs_trystatfile(FAR struct inode *inode,
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@ -547,7 +627,7 @@ static int unionfs_tryrmdir(FAR struct inode *inode, FAR const char *relpath,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -579,7 +659,7 @@ static int unionfs_tryunlink(FAR struct inode *inode,
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/* Is this path valid on this file system? */
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trypath = unionfs_trypath(relpath, prefix);
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trypath = unionfs_offsetpath(relpath, prefix);
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if (trypath == NULL)
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{
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/* No.. return -ENOENT */
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@ -725,7 +805,7 @@ static void unionfs_destroy(FAR struct unionfs_inode_s *ui)
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/* Free any allocated prefix strings */
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if (ui->ui_fs[1].um_prefix)
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if (ui->ui_fs[0].um_prefix)
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{
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kmm_free(ui->ui_fs[0].um_prefix);
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}
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@ -1280,10 +1360,6 @@ static int unionfs_opendir(FAR struct inode *mountpt, FAR const char *relpath,
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/* Check file system 2 first. */
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fu->fu_ndx = 0;
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fu->fu_lower[0] = NULL;
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fu->fu_lower[1] = NULL;
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um = &ui->ui_fs[1];
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lowerdir->fd_root = um->um_node;
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ret = unionfs_tryopendir(um->um_node, relpath, um->um_prefix, lowerdir);
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@ -1304,6 +1380,18 @@ static int unionfs_opendir(FAR struct inode *mountpt, FAR const char *relpath,
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}
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}
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/* Check if the user is stat'ing some "fake" node between the unionfs root and
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* the file system 1/2 root directory.
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*/
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else if (unionfs_ispartprefix(relpath, ui->ui_fs[1].um_prefix))
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{
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/* File system 2 prefix includes this relpath */
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fu->fu_ndx = 1;
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fu->fu_prefix[1] = true;
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}
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/* Check file system 1 last, possibly overwriting fu_ndx */
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um = &ui->ui_fs[0];
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@ -1324,14 +1412,28 @@ static int unionfs_opendir(FAR struct inode *mountpt, FAR const char *relpath,
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kmm_free(lowerdir);
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/* If the directory was not found on either file system, then we have
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* failed.
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/* Check if the user is stat'ing some "fake" node between the unionfs
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* root and the file system 1 root directory.
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*/
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if (fu->fu_lower[1] == NULL)
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if (unionfs_ispartprefix(relpath, ui->ui_fs[0].um_prefix))
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{
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/* Neither file system was opened! */
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/* File system 1 offset includes this relpath. Make sure that only one */
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fu->fu_ndx = 0;
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fu->fu_prefix[0] = true;
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fu->fu_prefix[1] = false;
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}
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/* If the directory was not found on either file system, then we have
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* failed to open this path on either file system.
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*/
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else if (fu->fu_lower[1] == NULL && !fu->fu_prefix[1])
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{
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/* Neither of the two path file systems include this relpath */
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ret = -ENOENT;
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goto errout_with_relpath;
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}
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}
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@ -1472,10 +1574,63 @@ static int unionfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
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DEBUGASSERT(dir);
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fu = &dir->u.unionfs;
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/* Check if we are at the end of the the directory listing. */
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if (fu->fu_eod)
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{
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/* End of file and error conditions are not distinguishable
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* with readdir. Here we return -ENOENT to signal the end
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* of the directory.
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*/
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return -ENOENT;
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}
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DEBUGASSERT(fu->fu_ndx == 0 || fu->fu_ndx == 1);
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um = &ui->ui_fs[fu->fu_ndx];
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DEBUGASSERT(um != NULL && um->um_node != NULL && um->um_node->u.i_mops != NULL);
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/* Special case: If the open directory is a 'fake' node in the prefix on
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* one of the mounted file system, then we must also fake the return value.
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*/
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if (fu->fu_prefix[fu->fu_ndx])
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{
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DEBUGASSERT(fu->fu_lower[fu->fu_ndx] == NULL && um->um_prefix != NULL);
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/* Copy the file system offset into the dirent structure.
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* REVISIT: This will not handle the case where the prefix contains
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* the '/' character the so the offset appears to be multiple
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* directories.
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*/
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strncpy(dir->fd_dir.d_name, um->um_prefix, NAME_MAX+1);
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/* Describe this as a read only directory */
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dir->fd_dir.d_type = DTYPE_DIRECTORY;
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/* Increment the index to file system 2 (maybe) */
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if (fu->fu_ndx == 0 && (fu->fu_prefix[1] || fu->fu_lower[1] != NULL))
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{
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/* Yes.. set up to do file system 2 next time */
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fu->fu_ndx++;
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}
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else
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{
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/* No.. we are finished */
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fu->fu_eod = true;
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}
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return OK;
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}
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/* This is a normal, mediated file system readdir() */
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DEBUGASSERT(fu->fu_lower[fu->fu_ndx] != NULL);
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DEBUGASSERT(um->um_node != NULL && um->um_node->u.i_mops != NULL);
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ops = um->um_node->u.i_mops;
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fvdbg("fu_ndx: %d\n", fu->fu_ndx);
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@ -1498,29 +1653,99 @@ static int unionfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
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* move to the second file system (if there is one).
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*/
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if (ret == -ENOENT && fu->fu_ndx == 0 && fu->fu_lower[1] != NULL)
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if (ret == -ENOENT && fu->fu_ndx == 0)
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{
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/* Switch to the second file system */
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fu->fu_ndx = 1;
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um = &ui->ui_fs[1];
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DEBUGASSERT(um != NULL && um->um_node != NULL &&
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um->um_node->u.i_mops != NULL);
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ops = um->um_node->u.i_mops;
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/* Make sure that the second file system directory enumeration
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* is rewound to the beginning of the directory.
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/* Special case: If the open directory is a 'fake' node in the
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* prefix on file system2, then we must also fake the return
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* value.
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*/
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if (ops->rewinddir != NULL)
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if (fu->fu_prefix[1])
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{
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ret = ops->rewinddir(um->um_node, fu->fu_lower[1]);
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DEBUGASSERT(fu->fu_lower[1] == NULL);
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/* Switch to the second file system */
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fu->fu_ndx = 1;
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um = &ui->ui_fs[1];
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DEBUGASSERT(um != NULL && um->um_prefix != NULL);
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/* Copy the file system offset into the dirent structure.
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* REVISIT: This will not handle the case where the prefix
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* contains the '/' character the so the offset appears to
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* be multiple directories.
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*/
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strncpy(dir->fd_dir.d_name, um->um_prefix, NAME_MAX+1);
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/* Describe this as a read only directory */
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dir->fd_dir.d_type = DTYPE_DIRECTORY;
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/* Mark the end of the directory listing */
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fu->fu_eod = true;
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/* Check if have already reported something of this name in file system 1. */
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relpath = unionfs_relpath(fu->fu_relpath, um->um_prefix);
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if (relpath)
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{
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int tmp;
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/* Check if anything exists at this path on file system 1 */
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um0 = &ui->ui_fs[0];
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tmp = unionfs_trystat(um0->um_node, relpath,
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um0->um_prefix, &buf);
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/* Free the allocated relpath */
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kmm_free(relpath);
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/* Check for a duplicate */
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if (tmp >= 0)
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{
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/* There is something there!
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* REVISIT: We could allow files and directories to
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* have duplicat names.
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*/
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return -ENOENT;
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}
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}
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return OK;
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}
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/* No.. check for a normal directory access */
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else if (fu->fu_lower[1] != NULL)
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{
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/* Switch to the second file system */
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fu->fu_ndx = 1;
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um = &ui->ui_fs[1];
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DEBUGASSERT(um != NULL && um->um_node != NULL &&
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um->um_node->u.i_mops != NULL);
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ops = um->um_node->u.i_mops;
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/* Make sure that the second file system directory enumeration
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* is rewound to the beginning of the directory.
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*/
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if (ops->rewinddir != NULL)
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{
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ret = ops->rewinddir(um->um_node, fu->fu_lower[1]);
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}
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/* Then try the read operation again */
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ret = ops->readdir(um->um_node, fu->fu_lower[1]);
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}
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/* Then try the read operation again */
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ret = ops->readdir(um->um_node, fu->fu_lower[1]);
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}
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/* Did we successfully read a directory from file system 2? If
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@ -1612,28 +1837,32 @@ static int unionfs_rewinddir(struct inode *mountpt, struct fs_dirent_s *dir)
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*/
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DEBUGASSERT(fu->fu_ndx == 0 || fu->fu_ndx == 1);
|
||||
if (/* fu->fu_ndx != 0 && */ fu->fu_lower[0] != 0)
|
||||
if (/* fu->fu_ndx != 0 && */ fu->fu_prefix[0] || fu->fu_lower[0] != NULL)
|
||||
{
|
||||
/* Yes.. switch to file system 1 */
|
||||
|
||||
fu->fu_ndx = 0;
|
||||
}
|
||||
|
||||
um = &ui->ui_fs[fu->fu_ndx];
|
||||
|
||||
DEBUGASSERT(um != NULL && um->um_node != NULL && um->um_node->u.i_mops != NULL);
|
||||
ops = um->um_node->u.i_mops;
|
||||
|
||||
/* Perform the file system rewind operation */
|
||||
|
||||
if (ops->rewinddir != NULL)
|
||||
if (!fu->fu_prefix[fu->fu_ndx])
|
||||
{
|
||||
ret = ops->rewinddir(um->um_node, fu->fu_lower[fu->fu_ndx]);
|
||||
dir->fd_position = fu->fu_lower[fu->fu_ndx]->fd_position;
|
||||
}
|
||||
else
|
||||
{
|
||||
ret = -EINVAL;
|
||||
DEBUGASSERT(fu->fu_lower[fu->fu_ndx] != NULL);
|
||||
um = &ui->ui_fs[fu->fu_ndx];
|
||||
|
||||
DEBUGASSERT(um != NULL && um->um_node != NULL && um->um_node->u.i_mops != NULL);
|
||||
ops = um->um_node->u.i_mops;
|
||||
|
||||
/* Perform the file system rewind operation */
|
||||
|
||||
if (ops->rewinddir != NULL)
|
||||
{
|
||||
ret = ops->rewinddir(um->um_node, fu->fu_lower[fu->fu_ndx]);
|
||||
dir->fd_position = fu->fu_lower[fu->fu_ndx]->fd_position;
|
||||
}
|
||||
else
|
||||
{
|
||||
ret = -EINVAL;
|
||||
}
|
||||
}
|
||||
|
||||
unionfs_semgive(ui);
|
||||
@ -1831,7 +2060,7 @@ static int unionfs_unlink(FAR struct inode *mountpt,
|
||||
struct stat buf;
|
||||
int ret;
|
||||
|
||||
fdbg("relpath: %s\n", relpath);
|
||||
fvdbg("relpath: %s\n", relpath);
|
||||
|
||||
/* Recover the union file system data from the struct inode instance */
|
||||
|
||||
@ -1902,7 +2131,7 @@ static int unionfs_mkdir(FAR struct inode *mountpt, FAR const char *relpath,
|
||||
int ret2;
|
||||
int ret;
|
||||
|
||||
fdbg("relpath: %s\n", relpath);
|
||||
fvdbg("relpath: %s\n", relpath);
|
||||
|
||||
/* Recover the union file system data from the struct inode instance */
|
||||
|
||||
@ -1975,7 +2204,7 @@ static int unionfs_rmdir(FAR struct inode *mountpt, FAR const char *relpath)
|
||||
int tmp;
|
||||
int ret;
|
||||
|
||||
fdbg("relpath: %s\n", relpath);
|
||||
fvdbg("relpath: %s\n", relpath);
|
||||
|
||||
/* Recover the union file system data from the struct inode instance */
|
||||
|
||||
@ -2050,7 +2279,7 @@ static int unionfs_rename(FAR struct inode *mountpt,
|
||||
int tmp;
|
||||
int ret = -ENOENT;
|
||||
|
||||
fdbg("oldrelpath: %s newrelpath\n", oldrelpath, newrelpath);
|
||||
fvdbg("oldrelpath: %s newrelpath\n", oldrelpath, newrelpath);
|
||||
|
||||
/* Recover the union file system data from the struct inode instance */
|
||||
|
||||
@ -2124,7 +2353,7 @@ static int unionfs_stat(FAR struct inode *mountpt, FAR const char *relpath,
|
||||
FAR struct unionfs_mountpt_s *um;
|
||||
int ret;
|
||||
|
||||
fdbg("relpath: %s\n", relpath);
|
||||
fvdbg("relpath: %s\n", relpath);
|
||||
|
||||
/* Recover the union file system data from the struct inode instance */
|
||||
|
||||
@ -2157,6 +2386,44 @@ static int unionfs_stat(FAR struct inode *mountpt, FAR const char *relpath,
|
||||
|
||||
um = &ui->ui_fs[1];
|
||||
ret = unionfs_trystat(um->um_node, relpath, um->um_prefix, buf);
|
||||
if (ret >= 0)
|
||||
{
|
||||
/* Return on the first success. The first instance of the file will
|
||||
* shadow the second anyway.
|
||||
*/
|
||||
|
||||
unionfs_semgive(ui);
|
||||
return OK;
|
||||
}
|
||||
|
||||
/* Special case the unionfs root directory when both file systems are offset.
|
||||
* In that case, both of the above trystat calls will fail.
|
||||
*/
|
||||
|
||||
if (ui->ui_fs[0].um_prefix != NULL && ui->ui_fs[1].um_prefix != NULL)
|
||||
{
|
||||
/* Most of the stat entries just do not apply */
|
||||
|
||||
memset(buf, 0, sizeof(struct stat));
|
||||
|
||||
/* Claim that this is a read-only directory */
|
||||
|
||||
buf->st_mode = S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR;
|
||||
|
||||
/* Check if the user is stat'ing some "fake" node between the unionfs
|
||||
* root and the file system 1 root directory.
|
||||
*/
|
||||
|
||||
if (unionfs_ispartprefix(relpath, ui->ui_fs[0].um_prefix) ||
|
||||
unionfs_ispartprefix(relpath, ui->ui_fs[1].um_prefix))
|
||||
{
|
||||
ret = OK;
|
||||
}
|
||||
else
|
||||
{
|
||||
ret = -ENOENT;
|
||||
}
|
||||
}
|
||||
|
||||
unionfs_semgive(ui);
|
||||
return ret;
|
||||
|
||||
@ -157,6 +157,8 @@ struct fs_dirent_s; /* Forward reference */
|
||||
struct fs_unionfsdir_s
|
||||
{
|
||||
uint8_t fu_ndx; /* Index of file system being enumerated */
|
||||
bool fu_eod; /* True: At end of directory */
|
||||
bool fu_prefix[2]; /* True: Fake directory in prefix */
|
||||
FAR char *fu_relpath; /* Path being enumerated */
|
||||
FAR struct fs_dirent_s *fu_lower[2]; /* dirent struct used by contained file system */
|
||||
};
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user