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/ChangeLog b/fs/ntfs/ChangeLog
index 4af6ae6..7507a56 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -92,6 +92,11 @@
non-resident in fs/ntfs/attrib.c::ntfs_attr_can_be_non_resident().
- Add fs/ntfs/attrib.c::ntfs_attr_vcn_to_lcn_nolock() used by the new
write code.
+ - 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 fs/ntfs/attrib.c::ntfs_find_vcn_nolock() to
+ ntfs_attr_find_vcn_nolock() and update all callers.
2.1.22 - Many bug and race fixes and error handling improvements.
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) {
diff --git a/fs/ntfs/attrib.h b/fs/ntfs/attrib.h
index 75041c8..e0a50f1c 100644
--- a/fs/ntfs/attrib.h
+++ b/fs/ntfs/attrib.h
@@ -66,8 +66,8 @@
extern LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked);
-extern runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
- const BOOL write_locked);
+extern runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni,
+ const VCN vcn, const BOOL write_locked);
int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
const u32 name_len, const IGNORE_CASE_BOOL ic,
diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c
index f2b7f85..6e584ab 100644
--- a/fs/ntfs/lcnalloc.c
+++ b/fs/ntfs/lcnalloc.c
@@ -850,7 +850,7 @@
/* This returns with ni->runlist locked for reading on success. */
down_read(&ni->runlist.lock);
- rl = ntfs_find_vcn_nolock(ni, start_vcn, FALSE);
+ rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, FALSE);
if (IS_ERR(rl)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to find first runlist "
@@ -904,7 +904,7 @@
/* Attempt to map runlist. */
vcn = rl->vcn;
- rl = ntfs_find_vcn_nolock(ni, vcn, FALSE);
+ rl = ntfs_attr_find_vcn_nolock(ni, vcn, FALSE);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (!is_rollback)
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 66ef6e2..61ce09f 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -1297,7 +1297,7 @@
read_lock_irqsave(&mftbmp_ni->size_lock, flags);
ll = mftbmp_ni->allocated_size;
read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
- rl = ntfs_find_vcn_nolock(mftbmp_ni,
+ rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
(ll - 1) >> vol->cluster_size_bits, TRUE);
if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
up_write(&mftbmp_ni->runlist.lock);
@@ -1727,8 +1727,8 @@
read_lock_irqsave(&mft_ni->size_lock, flags);
ll = mft_ni->allocated_size;
read_unlock_irqrestore(&mft_ni->size_lock, flags);
- rl = ntfs_find_vcn_nolock(mft_ni, (ll - 1) >> vol->cluster_size_bits,
- TRUE);
+ rl = ntfs_attr_find_vcn_nolock(mft_ni,
+ (ll - 1) >> vol->cluster_size_bits, TRUE);
if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
up_write(&mft_ni->runlist.lock);
ntfs_error(vol->sb, "Failed to determine last allocated "
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
index 1b344dd..3f479f1 100644
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -933,17 +933,18 @@
*
* It is up to the caller to serialize access to the runlist @rl.
*
- * Since lcns must be >= 0, we use negative return values with special meaning:
+ * Since lcns must be >= 0, we use negative return codes with special meaning:
*
- * Return value Meaning / Description
+ * Return code Meaning / Description
* ==================================================
- * -1 = LCN_HOLE Hole / not allocated on disk.
- * -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been
- * inserted into the runlist yet.
- * -3 = LCN_ENOENT There is no such vcn in the attribute.
+ * LCN_HOLE Hole / not allocated on disk.
+ * LCN_RL_NOT_MAPPED This is part of the runlist which has not been
+ * inserted into the runlist yet.
+ * LCN_ENOENT There is no such vcn in the attribute.
*
* Locking: - The caller must have locked the runlist (for reading or writing).
- * - This function does not touch the lock.
+ * - This function does not touch the lock, nor does it modify the
+ * runlist.
*/
LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
{
diff --git a/fs/ntfs/runlist.h b/fs/ntfs/runlist.h
index 7107fde..60c42f3 100644
--- a/fs/ntfs/runlist.h
+++ b/fs/ntfs/runlist.h
@@ -66,6 +66,8 @@
LCN_HOLE = -1, /* Keep this as highest value or die! */
LCN_RL_NOT_MAPPED = -2,
LCN_ENOENT = -3,
+ LCN_ENOMEM = -4,
+ LCN_EIO = -5,
} LCN_SPECIAL_VALUES;
extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
