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-rw-r--r--fs/ubifs/file.c13
-rw-r--r--fs/ubifs/ubifs.h2
2 files changed, 9 insertions, 6 deletions
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index c726da68e6be..12f445cee9f7 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -967,12 +967,15 @@ static int do_writepage(struct page *page, int len)
967 * the page locked, and it locks @ui_mutex. However, write-back does take inode 967 * the page locked, and it locks @ui_mutex. However, write-back does take inode
968 * @i_mutex, which means other VFS operations may be run on this inode at the 968 * @i_mutex, which means other VFS operations may be run on this inode at the
969 * same time. And the problematic one is truncation to smaller size, from where 969 * same time. And the problematic one is truncation to smaller size, from where
970 * we have to call 'vmtruncate()', which first changes @inode->i_size, then 970 * we have to call 'simple_setsize()', which first changes @inode->i_size, then
971 * drops the truncated pages. And while dropping the pages, it takes the page 971 * drops the truncated pages. And while dropping the pages, it takes the page
972 * lock. This means that 'do_truncation()' cannot call 'vmtruncate()' with 972 * lock. This means that 'do_truncation()' cannot call 'simple_setsize()' with
973 * @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This 973 * @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This
974 * means that @inode->i_size is changed while @ui_mutex is unlocked. 974 * means that @inode->i_size is changed while @ui_mutex is unlocked.
975 * 975 *
976 * XXX: with the new truncate the above is not true anymore, the simple_setsize
977 * calls can be replaced with the individual components.
978 *
976 * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond 979 * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
977 * inode size. How do we do this if @inode->i_size may became smaller while we 980 * inode size. How do we do this if @inode->i_size may became smaller while we
978 * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the 981 * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
@@ -1125,7 +1128,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
1125 budgeted = 0; 1128 budgeted = 0;
1126 } 1129 }
1127 1130
1128 err = vmtruncate(inode, new_size); 1131 err = simple_setsize(inode, new_size);
1129 if (err) 1132 if (err)
1130 goto out_budg; 1133 goto out_budg;
1131 1134
@@ -1214,7 +1217,7 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
1214 1217
1215 if (attr->ia_valid & ATTR_SIZE) { 1218 if (attr->ia_valid & ATTR_SIZE) {
1216 dbg_gen("size %lld -> %lld", inode->i_size, new_size); 1219 dbg_gen("size %lld -> %lld", inode->i_size, new_size);
1217 err = vmtruncate(inode, new_size); 1220 err = simple_setsize(inode, new_size);
1218 if (err) 1221 if (err)
1219 goto out; 1222 goto out;
1220 } 1223 }
@@ -1223,7 +1226,7 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
1223 if (attr->ia_valid & ATTR_SIZE) { 1226 if (attr->ia_valid & ATTR_SIZE) {
1224 /* Truncation changes inode [mc]time */ 1227 /* Truncation changes inode [mc]time */
1225 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode); 1228 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1226 /* 'vmtruncate()' changed @i_size, update @ui_size */ 1229 /* 'simple_setsize()' changed @i_size, update @ui_size */
1227 ui->ui_size = inode->i_size; 1230 ui->ui_size = inode->i_size;
1228 } 1231 }
1229 1232
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index b0904536cc1c..2eef553d50c8 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -379,7 +379,7 @@ struct ubifs_gced_idx_leb {
379 * The @ui_size is a "shadow" variable for @inode->i_size and UBIFS uses 379 * The @ui_size is a "shadow" variable for @inode->i_size and UBIFS uses
380 * @ui_size instead of @inode->i_size. The reason for this is that UBIFS cannot 380 * @ui_size instead of @inode->i_size. The reason for this is that UBIFS cannot
381 * make sure @inode->i_size is always changed under @ui_mutex, because it 381 * make sure @inode->i_size is always changed under @ui_mutex, because it
382 * cannot call 'vmtruncate()' with @ui_mutex locked, because it would deadlock 382 * cannot call 'simple_setsize()' with @ui_mutex locked, because it would deadlock
383 * with 'ubifs_writepage()' (see file.c). All the other inode fields are 383 * with 'ubifs_writepage()' (see file.c). All the other inode fields are
384 * changed under @ui_mutex, so they do not need "shadow" fields. Note, one 384 * changed under @ui_mutex, so they do not need "shadow" fields. Note, one
385 * could consider to rework locking and base it on "shadow" fields. 385 * could consider to rework locking and base it on "shadow" fields.