From bbf1813fb8ff9d21171bf22e6d1f0e0393601e86 Mon Sep 17 00:00:00 2001 From: Anton Altaparmakov Date: Thu, 8 Sep 2005 21:09:06 +0100 Subject: NTFS: Fix cluster (de)allocators to work when the runlist is NULL and more importantly to take a locked runlist rather than them locking it which leads to lock reversal. Signed-off-by: Anton Altaparmakov --- fs/ntfs/lcnalloc.c | 39 ++++++++++++++++----------------------- 1 file changed, 16 insertions(+), 23 deletions(-) (limited to 'fs/ntfs/lcnalloc.c') diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c index a4bc07616e5d..7b5934290685 100644 --- a/fs/ntfs/lcnalloc.c +++ b/fs/ntfs/lcnalloc.c @@ -54,6 +54,8 @@ int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol, int ret = 0; ntfs_debug("Entering."); + if (!rl) + return 0; for (; rl->length; rl++) { int err; @@ -163,17 +165,9 @@ runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn, BUG_ON(zone < FIRST_ZONE); BUG_ON(zone > LAST_ZONE); - /* Return empty runlist if @count == 0 */ - // FIXME: Do we want to just return NULL instead? (AIA) - if (!count) { - rl = ntfs_malloc_nofs(PAGE_SIZE); - if (!rl) - return ERR_PTR(-ENOMEM); - rl[0].vcn = start_vcn; - rl[0].lcn = LCN_RL_NOT_MAPPED; - rl[0].length = 0; - return rl; - } + /* Return NULL if @count is zero. */ + if (!count) + return NULL; /* Take the lcnbmp lock for writing. */ down_write(&vol->lcnbmp_lock); /* @@ -788,7 +782,8 @@ out: * @vi: vfs inode whose runlist describes the clusters to free * @start_vcn: vcn in the runlist of @vi at which to start freeing clusters * @count: number of clusters to free or -1 for all clusters - * @is_rollback: if TRUE this is a rollback operation + * @write_locked: true if the runlist is locked for writing + * @is_rollback: true if this is a rollback operation * * Free @count clusters starting at the cluster @start_vcn in the runlist * described by the vfs inode @vi. @@ -806,17 +801,17 @@ out: * Return the number of deallocated clusters (not counting sparse ones) on * success and -errno on error. * - * Locking: - The runlist described by @vi must be unlocked on entry and is - * unlocked on return. - * - This function takes the runlist lock of @vi for reading and - * sometimes for writing and sometimes modifies the runlist. + * Locking: - The runlist described by @vi must be locked on entry and is + * locked on return. Note if the runlist is locked for reading the + * lock may be dropped and reacquired. Note the runlist may be + * modified when needed runlist fragments need to be mapped. * - The volume lcn bitmap must be unlocked on entry and is unlocked * on return. * - This function takes the volume lcn bitmap lock for writing and * modifies the bitmap contents. */ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count, - const BOOL is_rollback) + const BOOL write_locked, const BOOL is_rollback) { s64 delta, to_free, total_freed, real_freed; ntfs_inode *ni; @@ -848,8 +843,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count, total_freed = real_freed = 0; - down_read(&ni->runlist.lock); - rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, FALSE); + rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, write_locked); if (IS_ERR(rl)) { if (!is_rollback) ntfs_error(vol->sb, "Failed to find first runlist " @@ -903,7 +897,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count, /* Attempt to map runlist. */ vcn = rl->vcn; - rl = ntfs_attr_find_vcn_nolock(ni, vcn, FALSE); + rl = ntfs_attr_find_vcn_nolock(ni, vcn, write_locked); if (IS_ERR(rl)) { err = PTR_ERR(rl); if (!is_rollback) @@ -950,7 +944,6 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count, /* Update the total done clusters. */ total_freed += to_free; } - up_read(&ni->runlist.lock); if (likely(!is_rollback)) up_write(&vol->lcnbmp_lock); @@ -960,7 +953,6 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count, ntfs_debug("Done."); return real_freed; err_out: - up_read(&ni->runlist.lock); if (is_rollback) return err; /* If no real clusters were freed, no need to rollback. */ @@ -973,7 +965,8 @@ err_out: * If rollback fails, set the volume errors flag, emit an error * message, and return the error code. */ - delta = __ntfs_cluster_free(vi, start_vcn, total_freed, TRUE); + delta = __ntfs_cluster_free(vi, start_vcn, total_freed, write_locked, + TRUE); if (delta < 0) { ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving " "inconsistent metadata! Unmount and run " -- cgit v1.2.3