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cifs: make cifs_rename handle -EACCES errors
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cifs: make cifs_rename handle -EACCES errors

Some servers seem to return -EACCES when attempting to rename one
open file on top of another. Refactor the cifs_rename logic to
attempt to rename the target file out of the way in this situation.

This also fixes the "unlink_target" logic to be undoable if the
subsequent rename fails.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Jeff Layton authored and Steve French committed Oct 20, 2008
1 parent 4134609 commit 14121bd
Showing 1 changed file with 122 additions and 52 deletions.
174 changes: 122 additions & 52 deletions fs/cifs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1285,30 +1285,32 @@ cifs_do_rename(int xid, struct dentry *from_dentry, const char *fromPath,
return rc;
}

int cifs_rename(struct inode *source_inode, struct dentry *source_direntry,
struct inode *target_inode, struct dentry *target_direntry)
int cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
struct inode *target_dir, struct dentry *target_dentry)
{
char *fromName = NULL;
char *toName = NULL;
struct cifs_sb_info *cifs_sb_source;
struct cifs_sb_info *cifs_sb_target;
struct cifsTconInfo *pTcon;
struct cifsTconInfo *tcon;
struct cifsInodeInfo *target_cinode;
FILE_UNIX_BASIC_INFO *info_buf_source = NULL;
FILE_UNIX_BASIC_INFO *info_buf_target;
int xid;
int rc;
__u16 dstfid;
int xid, rc, tmprc, oplock = 0;
bool delete_already_pending;

cifs_sb_target = CIFS_SB(target_inode->i_sb);
cifs_sb_source = CIFS_SB(source_inode->i_sb);
pTcon = cifs_sb_source->tcon;
cifs_sb_target = CIFS_SB(target_dir->i_sb);
cifs_sb_source = CIFS_SB(source_dir->i_sb);
tcon = cifs_sb_source->tcon;

xid = GetXid();

/*
* BB: this might be allowed if same server, but different share.
* Consider adding support for this
*/
if (pTcon != cifs_sb_target->tcon) {
if (tcon != cifs_sb_target->tcon) {
rc = -EXDEV;
goto cifs_rename_exit;
}
Expand All @@ -1317,65 +1319,133 @@ int cifs_rename(struct inode *source_inode, struct dentry *source_direntry,
* we already have the rename sem so we do not need to
* grab it again here to protect the path integrity
*/
fromName = build_path_from_dentry(source_direntry);
fromName = build_path_from_dentry(source_dentry);
if (fromName == NULL) {
rc = -ENOMEM;
goto cifs_rename_exit;
}

toName = build_path_from_dentry(target_direntry);
toName = build_path_from_dentry(target_dentry);
if (toName == NULL) {
rc = -ENOMEM;
goto cifs_rename_exit;
}

rc = cifs_do_rename(xid, source_direntry, fromName,
target_direntry, toName);
rc = cifs_do_rename(xid, source_dentry, fromName,
target_dentry, toName);

if (rc == -EEXIST) {
if (pTcon->unix_ext) {
/*
* Are src and dst hardlinks of same inode? We can
* only tell with unix extensions enabled
*/
info_buf_source =
kmalloc(2 * sizeof(FILE_UNIX_BASIC_INFO),
GFP_KERNEL);
if (info_buf_source == NULL)
goto unlink_target;

info_buf_target = info_buf_source + 1;
rc = CIFSSMBUnixQPathInfo(xid, pTcon, fromName,
info_buf_source,
cifs_sb_source->local_nls,
cifs_sb_source->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
if (rc != 0)
goto unlink_target;

rc = CIFSSMBUnixQPathInfo(xid, pTcon,
toName, info_buf_target,
cifs_sb_target->local_nls,
/* remap based on source sb */
cifs_sb_source->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
if (rc == -EEXIST && tcon->unix_ext) {
/*
* Are src and dst hardlinks of same inode? We can
* only tell with unix extensions enabled
*/
info_buf_source =
kmalloc(2 * sizeof(FILE_UNIX_BASIC_INFO),
GFP_KERNEL);
if (info_buf_source == NULL) {
rc = -ENOMEM;
goto cifs_rename_exit;
}

info_buf_target = info_buf_source + 1;
rc = CIFSSMBUnixQPathInfo(xid, tcon, fromName,
info_buf_source,
cifs_sb_source->local_nls,
cifs_sb_source->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
if (rc != 0)
goto unlink_target;

if (rc == 0 && (info_buf_source->UniqueId ==
info_buf_target->UniqueId))
/* same file, POSIX says that this is a noop */
goto cifs_rename_exit;
} /* else ... BB we could add the same check for Windows by
rc = CIFSSMBUnixQPathInfo(xid, tcon,
toName, info_buf_target,
cifs_sb_target->local_nls,
/* remap based on source sb */
cifs_sb_source->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);

if (rc == 0 && (info_buf_source->UniqueId ==
info_buf_target->UniqueId))
/* same file, POSIX says that this is a noop */
goto cifs_rename_exit;

rc = -EEXIST;
} /* else ... BB we could add the same check for Windows by
checking the UniqueId via FILE_INTERNAL_INFO */

if ((rc == -EACCES) || (rc == -EEXIST)) {
unlink_target:
/* don't bother if this is a negative dentry */
if (!target_dentry->d_inode)
goto cifs_rename_exit;

target_cinode = CIFS_I(target_dentry->d_inode);

/* try to move the target out of the way */
tmprc = CIFSSMBOpen(xid, tcon, toName, FILE_OPEN, DELETE,
CREATE_NOT_DIR, &dstfid, &oplock, NULL,
cifs_sb_target->local_nls,
cifs_sb_target->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
if (tmprc)
goto cifs_rename_exit;

/* rename the file to random name */
tmprc = CIFSSMBRenameOpenFile(xid, tcon, dstfid, NULL,
cifs_sb_target->local_nls,
cifs_sb_target->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);

if (tmprc)
goto close_target;

delete_already_pending = target_cinode->delete_pending;

if (!delete_already_pending) {
/* set delete on close */
tmprc = CIFSSMBSetFileDisposition(xid, tcon,
true, dstfid,
current->tgid);
/*
* This hack is for broken samba servers, remove this
* once more fixed ones are in the field.
*/
if (tmprc == -ENOENT)
delete_already_pending = false;
else if (tmprc)
goto undo_target_rename;

target_cinode->delete_pending = true;
}


rc = cifs_do_rename(xid, source_dentry, fromName,
target_dentry, toName);

if (rc == 0)
goto close_target;

/*
* we either can not tell the files are hardlinked (as with
* Windows servers) or files are not hardlinked. Delete the
* target manually before renaming to follow POSIX rather than
* Windows semantics
* after this point, we can't bother with error handling on
* the undo's. This is best effort since we can't do anything
* about failures here.
*/
cifs_unlink(target_inode, target_direntry);
rc = cifs_do_rename(xid, source_direntry, fromName,
target_direntry, toName);
if (!delete_already_pending) {
tmprc = CIFSSMBSetFileDisposition(xid, tcon,
false, dstfid,
current->tgid);
if (tmprc == 0)
target_cinode->delete_pending = false;
}

undo_target_rename:
/* rename failed: undo target rename */
CIFSSMBRenameOpenFile(xid, tcon, dstfid,
target_dentry->d_name.name,
cifs_sb_target->local_nls,
cifs_sb_target->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
close_target:
CIFSSMBClose(xid, tcon, dstfid);
}

cifs_rename_exit:
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