NTFS: - Fix bug in fs/ntfs/attrib.c::ntfs_find_vcn_nolock() where after
dropping the read lock and taking the write lock we were not checking
whether someone else did not already do the work we wanted to do.
- Rename ntfs_find_vcn_nolock() to ntfs_attr_find_vcn_nolock().
- Tidy up some comments in fs/ntfs/runlist.c.
- Add LCN_ENOMEM and LCN_EIO definitions to fs/ntfs/runlist.h.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 1610f1c..6de5e04 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -193,19 +193,19 @@
}
/**
- * ntfs_find_vcn_nolock - find a vcn in the runlist described by an ntfs inode
+ * ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode
* @ni: ntfs inode describing the runlist to search
* @vcn: vcn to find
* @write_locked: true if the runlist is locked for writing
*
* Find the virtual cluster number @vcn in the runlist described by the ntfs
* inode @ni and return the address of the runlist element containing the @vcn.
- * The runlist is left locked and the caller has to unlock it. In the error
- * case, the runlist is left in the same locking state as on entry.
*
- * Note if @write_locked is FALSE the lock may be dropped inside the function
- * so you cannot rely on the runlist still being the same when this function
- * returns.
+ * If the @vcn is not mapped yet, the attempt is made to map the attribute
+ * extent containing the @vcn and the vcn to lcn conversion is retried.
+ *
+ * If @write_locked is true the caller has locked the runlist for writing and
+ * if false for reading.
*
* Note you need to distinguish between the lcn of the returned runlist element
* being >= 0 and LCN_HOLE. In the later case you have to return zeroes on
@@ -221,13 +221,12 @@
* -ENOMEM - Not enough memory to map runlist.
* -EIO - Critical error (runlist/file is corrupt, i/o error, etc).
*
- * Locking: - The runlist must be unlocked on entry.
- * - On failing return, the runlist is unlocked.
- * - On successful return, the runlist is locked. If @need_write us
- * true, it is locked for writing. Otherwise is is locked for
- * reading.
+ * Locking: - The runlist must be locked on entry and is left locked on return.
+ * - If @write_locked is FALSE, i.e. the runlist is locked for reading,
+ * the lock may be dropped inside the function so you cannot rely on
+ * the runlist still being the same when this function returns.
*/
-runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
+runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked)
{
runlist_element *rl;
@@ -268,6 +267,12 @@
if (!write_locked) {
up_read(&ni->runlist.lock);
down_write(&ni->runlist.lock);
+ if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) !=
+ LCN_RL_NOT_MAPPED)) {
+ up_write(&ni->runlist.lock);
+ down_read(&ni->runlist.lock);
+ goto retry_remap;
+ }
}
err = ntfs_map_runlist_nolock(ni, vcn);
if (!write_locked) {